Device for forming annular grooves



June 8, 1943- A. RICKENMANN DEVICE FOR FORMING ANNULAR GROOVES Filed Dec. 16, 1941 I5 Sheets-Sheet 1 II T2 :1- w m W R. Nv 3 WW 7 T l I i A- 2 2 2 C H x u 33 11 FillFl llt Inventor June a, 1943.. A. RICKEIINMANN 2,321,421

DEVICE FOR FORMING ANNULAR GROOVES- Filed Dec. 16, 1941 3 Shee ts- Sheg-l; 3

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Patented June 8, 1943 DEVICE FOR FORMING ANNULAR GROOVES Alfred Rickenmann, Zurich, Switzerland; vested in the Alien Property Custodian Application December 16 1941, Serial No. 423,224

In Switzerland November 12, 1940 4 Claims.

The invention relates to a new and improved device for accurately forming annular grooves and ridges on a cylindrical workpiece such as is intended for turning grinding wheels for use in correcting screw threads and so on.

The invention relates more particularly to a device in which during a complete revolution of the cylindrical workpiece the latter is moved axially relative to the grinding disk by cams against the action of a spring a distance equal and opposite to the extent to which the grinding wheel is axially fed so that actually the grinding disk remains stationary in space while one of the annular grooves is being formed by said grinding disk. After one revolution of the cylindrical workpiece the said cams and the said spring effect a relative axial displacement of the grinding disk with reference to the cylindrical workpiece the said relative displacement is equal to the distance between the annular grooves.

The main object of the invention consists in theprovision of improved means to cross feed the grinding disk with reference to the cylindrical workpiece after an annular groove has been completed and before the formation of an adjacent one is being started.

s A tooth. on one face'of the sleeve i may be brought in and out of engagement with a notch on the spur wheelJ. In the shaft 5' a second shaft I is rotatably mounted carrying on the one end a cam disk I0 andon the other end a spur wheel 44 meshing with a toothed rim 8 of a sleeve #5.. The said sleeve 45 is rotatably mounted on ashaft l8 and meshes with a toothed rim 41 with the teeth 42 of the shaft 5. The shaft I is slidably arranged, a coiled spring 9 tends to press the said cam ID on to a corresponding camplate ll rigidly connected to the shaft 5. The workpiece I2 is held between the point 1 of the shaft 1 and point It slidably arranged in a bore of the tailstock C. The point it rests on a spring it which is compressed when the shaft I with the workpiece I2 is moved'in axial directidh.' The workvpiece l2 takes part of the rotation of the cam The inventionwill be better understood by.

reference to the following description in conjunction with the accompanying drawings.

In the accompanying drawings the preferred embodiment of the invention is shown in a diagrammatical manner.

Fig. 1 is a side elevation and Fig. 2 a front elevation of the new grinding machine Fig. 3 is a section taken on line III-III of Fig. 2 parts Fig. 4 is a section on the line IV--IV of Fig. 3

Fig. 5 illustrates the section of'the cross feeding device by a cam.

In the base A a headstock B, a tailstock C and a cross slide D are slidably and adiustably mounted on the ways E in the usual manner. In the base A a horizontal shaft 2 is journalled. The shaft 2 is driven from a motor shaft i by means of the spur wheels 4B, 4!. The shaft 2 is provided with an extension 2 having key 43 and on this extension 2 a spur wheel lis slidably arranged meshing with a spur wheel I loosely mounted on a shaft. 5 of the headstock B. The

gear 2 is secured against axial displacement by a hearing I] mounted on a screw-threaded spindle ii. The latter is iournalled in the base A disk I, a dog 49 fixed on said camdisk Ni engages a radial arm 50 attached to the workpiece l2.

The spur wheel ll of shaft 2 meshes with a spur wheel 52 rotatably mounted in the base A.

The wheel 52 drives by two universal joints 53 armed lever 24 mounted in the base A. The lever 24 actuates a shaft 2| by its free end 20. The

shaft2l is axially slidable and rotatably mounted in the base A. A screw threaded portion 55 of the spindle 2| engages a nut 28-forming part with the. casing I! of the cross slide D. In the casing It the grinding disk S is journalled adapttened which is slidably mounted in a cylinder 23.

The space behind the piston 22 is connected by a pipe 21 to the casing 51 of a distributing valve 58. In the casing 51 a piston 59 fixed on shaftis arranged having grooves to interconnect the port of pipe 21 with either the port of a pipe 26 or with the port of the exhaust pipe 30, By turning the valve piston 59 fluid under pressure may be forced into cylinder 23 or may be allowed to flow off, causing an axial displacement of the spindle 2i and of the cross slide D. The cross slide D maybe fed by means of the shaft 28 and two spur wheels 25, 36 and the screw threaded portion 55 of the lead screw 2| and nut 29. The shaft 28 may be turned by a hand wheel to bring the cross slide D to and from the workpiece l2. The arrangement of the parts is such that during a complete revolution of the shaft 5 and the workpiece I2 the latter is .moved axially by the cams I 0, II against the pressure of the spring I4 a distance equal t Fig. 3 and opposite to the extent if to which the shaft 5 and the headstock B are fed so that actually the grinding disk II remains stationary in space while one of the annular ridges is being formed. The ratio of rotation between the shafts 5 and I is 1 to2, the

shaft I makes two revolutions while shaft 5 makes but one. If shaft I is rotated in the direction of the arrow the carriage B is moved for a distance equal to t the distance between two adjacent annular ridges in the workpiece I2. As the speed at which the two shafts 5 and I run is different, the axial displacement of the workpiece I2 and of the carriage B takes place as described above for a like amount but in opposite direction. 'As soon as the workpiece I2 has completed a full revolution the grinding disk S is withdrawn from the workpiece by the cam 25. The shaft 5 and I8 run at the same speed. The

piston valve 59 is such that shortly before the follower Ill passes over the step incline II of cam II the pressure pipe is closed while at the same time the pipe 21 is connected with the flowoff pipe 30. The grinding disk S is withdrawn from the workpiece I2 shortly before the same has been shifted for'the distance t by the springs 9 and I4. The latter therefore shift the shaft I to the left Fig. 3, while the follower I passes over the incline II To start the withdrawal of the grinding disk S from the workpiece the follower 24 passes over the zone 0-1; of the cam 25 (Fig. The grinding disk S leaves the work piece by slow degrees. After the axial displaceinitial position. To attain this the clutch member 6 is moved to the left Fig. 3 and the space 23 is brought to communicate with the off-flow pipe 30. The workpiece I2 remains thereby stationary and the disk S is kept off the workpiece. The clutch member 6 has but one toothand the co-operating gear 4 but one notch to receive said tooth, therefore the parts assume automatically the correct relative position to ensure a correct setting of the disk S with reference to the groove pre-formed to allow a second cut.

What I wish to claim and secure by U. S. Letters Patent is:

1. A device for accurately forming annular grooves and ridges on a cylindrical workpiece of the type described comprising in combination a grinding disk, means for rotating and for axially feeding the workpiece, rotatable cam means for effecting continuous axial feeding between the ment of the workpiece I2 has taken place the valve 59 allows liquid under pressure to enter the space 23. grinding disk S on to the workpiece while the The piston 22 starts to feed the follower 24 passes over the point c of the cam 25. The feeding-in occurs gradually until the follower 24 passes over the point d. The gradient of the slopes a to b and c to d is low to prevent any jerky movement of the slide D. While the follower 24 passes from point d to point a the workpiece I2 makes at least one full turn. Dur-' ing this time the disk S remains in its working position.

After all the annular grooves have been formed, the grinding .disk S is returned to its said grinding disk and the workpiece at the rate of one groove of the workpiece for at least one complete revolution thereof, means for holding the grinding disk and the workpiece axially relatively to one another during a complete revolution, so that during the said whole revolution the grinding disk and the workpiece remain axially stationary relatively to one another, spring means independent of said cam means for effecting an axial return movement of the workpiece relatively to the grinding disk for a distance equal to the said advance feeding means for permanently constraining said grinding disc to a crossfeed movement away from the work, and meansrelation to the movement of the work piece.

4. A device as defined in claim 1 in which the control means to cross-feed the grinding disk are operated automatically, said means comprising a hydraulic device positively operated by the gearing which rotates the working piece.

. ALFRED RICKENMANN. 

